My U.S. Pat. No. 4,492,303, granted Jan. 8, 1985, discloses an early form of drive mechanism for a reciprocating floor conveyor. The system included extensible linear hydraulic motors connected at their cylinder ends to a frame structure and at their piston ends to push rods. The push rods were supported and guided at two locations by bearings. Between these locations the drive rods were connected to an equal number of transverse drive beams. The floor slat members were connected to the drive beams. This type of system required substantial bracing structure for the push rods, making the drive mechanism large and heavy.
The drive mechanism disclosed in my U.S. Pat. No. 4,793,469, granted Dec. 27, 1988, was designed to reduce the size and weight of the drive mechanism. In the system disclosed by this patent, the push rods were eliminated. The drive beams were directly connected to movable central portions of the linear hydraulic motors. Fixed opposite end portions of the motors were connected to transverse frame members which were in turn connected to frame portions of an installation. The invention of this patent was incorporated into the drive mechanism disclosed in my U.S. Pat. No. 4,748,893, granted Jun. 7, 1988. Thereafter, in an effort to further minimize the size and weight of the drive mechanism, I made the inventions which are disclosed in my U.S. Pat. No. 4,817,783, granted Apr. 4, 1989, my U.S. Pat. No. 4,969,387, granted Nov. 13, 1990, and in my U.S. Pat. No. 4,969,389, granted Nov. 13, 1990.
In each of the prior art systems described in the preceding paragraph there is a connection between the transverse drive beams, to which the floor members are attached, and the moving component of the linear hydraulic motor. Of necessity, the movable portion of the linear hydraulic motor had to be located below the transverse drive beams. This moved the centers of thrust of the motors away from the center of gravity of the floor members and made it necessary to utilize relatively heavy drive beams and substantial connections between the drive beams and the motors.
A principal object of the present invention is to provide a reciprocating floor conveyor in which the thrust lines of the linear hydraulic motors are raised, into positions closely adjacent the center of gravity of the floor members, and the size and weight of many of the conveyor components, including the transverse drive beams, are reduced.